Gas discharge lamp and power distribution system therefor

ABSTRACT

Fluorescent type lamps are arranged to have high frequency power derived from standard, commercial A.C. sources either directly or from power levels distributed from a master ballast. When the master ballast is employed, it functions as an interface between the primary power source and a distribution network to one or more modules so as to relieve the modules of operations such as initial power form conversions, filtering and power factor correcting which require large components. The module or modules driven by the master ballast output are contained within the lamp envelope or attached as an extension of the lamp envelope. The module is formed of elements mounted as a miniaturized unit configured to fit within the lamp envelope or to attach to the end of the envelope. The module includes oscillator components mounted on an elongated board so as to form an assembly with a cross-section compatible with the perimeter of the envelope itself. The module can operate independent of a master ballast unit by including power handling circuitry within the module.

This is a continuation of application Ser. No. 08/116,150 filed on Sep.2, 1993 now patented U.S. Pat. No. 5,485,057.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to gas discharge lamp apparatus andmethods as well as to power distribution systems and processes useful inassociation with such lamps although the power distribution feature isnot necessarily limited to the discharge lamp application. Moreparticularly, the present invention relates to fluorescent lamps,mercury vapor lamps, sodium or metal halide lamps, as well as to otherelectronic loads. This invention is especially useful for lightingsystems and power distribution associated with such lighting systems.

2. Description of the Prior Art

Contemporary lighting systems distribute power, such as at 60 Hertz, 115volts RMS (or 220 volts RMS), to a variety of fixtures containing gasdischarge lamps. Within each fixture is a solid state ballast whichfunctions as an electronic controller to filter and convert the A.C.power to direct current. The D.C. is next converted to a sinusoidalsource, such as 20 kilohertz, to provide operating power to the lamps.Examples of prior art ballast circuits for fluorescent lamps are shownin U.S. Pat. Nos. 3,753,071 by Engel et al; 4,109,307 by Knoll; and4,259,614 by Kohler, as well in the Patent Cooperation TreatyPublication WO 91/16802 by Smallwood et al.

Distributed power systems for fluorescent lamps are known in the priorart, such as in U.S. Pat. Nos. 4,508,996 by Clegg et al and 5,047,696 byNilssen. Clegg et al show D.C. driver inverters for producing highfrequency signals for driving clusters of lamps. Nilssen convertsprimary line power to D.C., and then to 30 kHz in an inverter forparallel distribution to a plurality of light units. Power is coupledthrough a passive auto-transformer network to drive fluorescent lightbulbs in pairs. The Clegg et al patent employs resonant circuits.

The prior art power distribution system for use in mines includes powerunits employing a signal at 30 kHz to drive a plurality of lamps, suchas in British Patent 1,401,628. U.S. Pat. No. 4,293,799 by Robertscolumn 1, lines 32-42, describes the prior art to their patent asincluding a system wherein a plurality of "intrinsic safety" mine lampsare powered by a common power unit in a manner suggested by theaforementioned British patent. The Roberts patent shows a master unitdriving a plurality of parallel connected slave units, and alleges itscontribution is an improvement to such a system in the form of voltagecontrol elements in-line between the master oscillator and the slavetype units to reduce the prospect of sparking. That is, the Robertspatent includes a voltage controller between the power source and theseries circuit, including the primary winding of a transformer forlimiting the amount of power to a level below that which is "incendiveto the atmosphere" for mine safety.

Various prior art has addressed modification of lamp envelopes toinclude different components. For instance, U.S. Pat. No. 4,571,526 byWesselink shows a mercury vapor lamp configured with the dischargeelements surrounding the ballast as a sealed unit. A special heatconductive thin-walled member is included for the ballast. U.S. Pat. No.3,549,941 by Friedmann shows fluorescent lamps having starter elements,a relay and operational elements all within the lamp envelope.

U.S. Pat. No. 4,316,121 by Hammer et al also shows a lamp ballast andfluorescent bulb packaging unit. It utilizes an inductive-resistiveelement formed as an elongated coil parallel to the lamp tube. U.S. Pat.No. 4,857,806 by Nilssen is another form of folded lamp with ballastingcircuitry in the base so it can accommodate screwing into a standardsocket.

Each ballast must ensure low electromagnetic radiation, must reduceconducted noise reflected into the main power line from its internalelectronics, and ideally should present as near as possible a unitypower factor to the main A.C. power mains.

The contemporary fluorescent lamp ballasts typically contain rectifiers,capacitors, transistors, integrated circuits and transformers toaccomplish the power conversion function. Each ballast may contain inexcess of forty individual components. While a single ballast may powerfrom one to four or more gas discharge lamps at one time, for largedistributed lighting requirements in factories and department stores,for instance, thousands of these controllers are required.

SUMMARY OF THE INVENTION

Traditional systems require a solid state ballast to both condition theinput A.C. power and to provide high frequency sinusoidal power to thelamps. The input A.C. power conditioning includes surge protection,filtering and more recently active input power factor correctioncircuitry. The output or lamp drive circuitry contains a high frequencyoscillator and transformer. The traditional ballast is a large unit(i.e., about twenty-five cubic inches) which requires a certifiedelectrician to install.

One of the features of the present invention is a high frequencyoscillator circuit miniaturized for containment within the envelope of alamp, or as a small module attached to the end of the lamp. The poweroscillator volume is a cylinder of less than five cubic inches.Sufficient circuitry is provided such that the lamp will function eitheras a stand-alone unit connected to primary A.C. power, or as a slaveunit connected to a power factor correction unit as a master in large,multiple fixture installations.

The present invention is concerned with the apparatus and method ofconstruction of a module for driving a gas discharge lamp having heaterelements contained within an envelope and for doing this in response toelectrical power from a source. Power is received from that source withan oscillator coupled to the received power for transforming thatreceived power to an output signal at a frequency and voltage suitablefor causing the lamp to produce visible light through gas dischargewithin the lamp envelope. An elongated circuit board mounts theoscillator within a volume having a cross-section configuredsubstantially the same as the cross-section of the lamp envelope. Theboard is attached for forming an end of the lamp envelope with theoscillator output signal connected to the lamp heater elements.

With the circuit board positioned within the lamp envelope, the power isreceivable via prong-type conductor pins extending from an endcap. It ispossible to attach the circuit board externally to an end of the lampenvelope with the module including a sleeve for retaining the boardtherewithin. The power source can produce standard A.C. power with themodule further including a circuit mounted on the circuit board forconverting the received A.C. power for actuating the oscillator. If thepower source produces D.C. power, the module includes means foractuating the oscillator from the received power from the D.C. source.

Typically, fluorescent lamp envelopes contain first and second heaterelements at respective ends of the envelope. A module, in accordancewith this invention, includes a direct connection of heater power fromthe oscillator output to the first of the heater elements. The modulefurther includes conductors extending the length of the envelope to thesecond of the heater elements for connecting the oscillator outputthereto. These conductors are preferably positioned along the innersurface of the envelope to minimize damage in handling.

The power factor correction unit employed in the present invention isdesigned to accept conventional 50/60 Hz A.C. power to filter and powerfactor correct this energy, and to provide smooth D.C. voltage, such as110 volts. The power factor correction unit may supply from one to tensof fluorescent ballast lamps in parallel. In small lamp installations,such as for workshop or home use, the ballast lamp will functiondirectly from the main A.C. power lines without the necessity of anintervening power factor correction unit.

Additionally, in large, multiple fixture installations, a qualifiedelectrician is not required to install numerous individual ballasts. Thewiring is simplified to attaching A.C. power only to the fixture as theballast is wholly contained with the lamp.

The simplicity of the slave ballast units permits configuring thoseslaves so they will fit as an attachment module on the end of afluorescent lamp. Alternatively, manufacture of the lamps can includethe slave ballast as an integral part thereof.

A conventional gas discharge lamp is designed to include a miniatureelectronic power oscillator which will both heat the cathode and supplythe necessary high voltage and current to illuminate the fluorescenttype of gas discharge tube. The electronics is constructed into a modulewhich fits completely inside the envelope of the gas discharge lamp, oris attachable as a module to the end of the lamp envelope. At one end ofthe tube, electrodes are provided to connect a D.C. source of energy,such as 110 volts or conventional 110 volts AC, 60 Hz, which suppliespower to the internal electronic oscillator. The electronics andassociated electrodes are constructed in one integrated assembly whichaides in the manufacture, test, and assembly of the lamp.

Additionally, the unit is so constructed as to optimize the heat removalfrom the circuitry. The power oscillator internal to the tube producessine wave power at several hundred kilohertz which aides in reducing thesize of the internal magnetic components as well as in minimizing theelectromagnetic field emissions from the lamp. The miniature poweroscillator is placed in a ferrous metal cylinder to facilitate heattransfer and reduce electromagnetic radiation.

The direct current (110 volts D.C., for example) potential required tooperate the ballast lamp is designed with a magnitude which is easilyderived from conventional existing 50 Hz or 60 Hz power sources. Thesize and power level of the D.C. source is selected so as to enablepowering from one ballast lamp to tens of them in parallel. The ballastlamp thus makes possible fluorescent lighting systems with centralizedpower conditioning equipment. Such new systems eliminate bulky andredundant ballasts which are presently required to operate fluorescentlighting systems. The two-pronged connector at one end of the lampfacilitates installing or changing lamps which are mountable, eithervertically or horizontally, while retaining the relative stability ofcontemporary fixtures for receiving elongated fluorescent lamps.

Another feature of the present invention relates to placement within thegas discharge lamp envelope a complete, highly efficient poweroscillator circuit, thereby eliminating bulky components which arepresently mounted external to the lamp. A single electronic assembly isprovided through the use of integrated circuits and surface mounttechnology which will enable manufacture of the gas discharge lamp inaccordance with this invention in a simple, reliable process. Theinvention permits design of a unit for D.C. input levels which arereadily obtainable from existing conventional A.C. power sources,thereby adding to the universality of the lamp.

A second feature of the present invention relates to apparatus andprocesses for separating the power conditioning elements associated witha fluorescent lighting system in a common master ballast unit whichparallel feeds a plurality of slave ballast units either attached to, orembedded in, the envelope of an elongated fluorescent type lamp. Whilethe invention is primarily intended for fluorescent systems, it isbelieved it may have wider power distribution significance.

Accordingly, the present invention is directed to a gas discharge lamppower distribution system for fluorescent lamps, or the like, and iscomposed of a master unit and one or more gas discharge lamps adapted tocooperate with that master unit. The master unit has an input and anoutput with the input receiving A.C. power from a source. Power factorcorrection is performed in the master unit, and reflected to the sourceat the master unit input. The A.C. power is converted to D.C. power atthe master unit output.

It is thus possible to parallel couple a plurality of gas dischargelamps to the master unit output. Each of those lamps is configured withan elongated envelope having a light producing medium contained therein.A module is associated with the envelope to interface with the masterunit output. The module includes a circuit board having an oscillatorcircuit mounted thereon, with that board positioned at one end of theelongated envelope. Further, the board assembly is constructed to have across-section conforming as an extension of the elongated envelope. Theoutput of the oscillator circuit is applied for exciting the medium, asby energizing heater elements and placing a potential across the mediumto cause it to produce light.

Those having normal skill in the art will recognize the foregoing andother objects, features, advantages and applications of the presentinvention from the following more detailed description of the preferredembodiments as illustrated in the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a typical prior art power distributionsystem for fluorescent lamps.

FIG. 2A is a fluorescent lamp power distribution system in accordancewith the present invention with ballast lamps coupled in paralleldirectly to an A.C. main.

FIG. 2B is a fluorescent lamp power distribution system in accordancewith the present invention powered by a converter and power factorcorrection master unit.

FIG. 3 is a general block diagram of the master conditioning unit of theFIG. 2B embodiment.

FIG. 4 is a somewhat idealized schematic diagram of a gas discharge lampincluding the power oscillator as in integral element thereof.

FIG. 5 is an alternate embodiment of an attachment of the ballast moduleto a lamp envelope.

FIG. 6 is a circuit diagram of a power oscillator suitable for use withthe ballast lamp structure of the present invention.

FIG. 7 is an isometric view of an electronics assembly constructed forplacement within a lamp envelope or for incorporation in a moduleattachable to the end of the lamp envelope.

FIG. 8 is a partially-sectioned view of a gas discharge lamp with theenvelope thereof formed in a U-shaped configuration with the controlelements contained within that envelope.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A conventional fluorescent lamp power distribution system is shown inschematic diagram form in FIG. 1 wherein standard input A.C. power 10 isintroduced at the input terminals. In the United States, this input isusually 60 Hz at 110 or 220 volts A.C. This power is introduced inparallel to a plurality of assemblies associated with each of an arrayof lamp fixtures. These assemblies include a converter, or ballast unit12A-12N which converts the primary A.C. input to a high frequency, suchas 20-30 kilohertz, to drive a set of typically two series connectedfluorescent lamps. Thus, ballast unit 12A drives lamps 14A and 15A inseries.

Lamp power distribution systems in accordance with this invention areshown in FIGS. 2A and 2B wherein the primary commercially-availablepower 10 is coupled to either system. A stand-alone configuration isshown in FIG. 2A wherein the main power 10 is connected in parallel intoa plurality of lamps 11A-11N each of which is self-sufficient in that itcontains its own power handling elements preferably including aconducted line noise filter and a power oscillator along the lines ofthose described later herein.

FIG. 2B is likewise driven by a conventional power system at input 10,but includes at least one master power converting unit 20 the output 22of which is coupled in parallel into a plurality of slave ballast lamps24A-24N. This reduces the amount of circuitry that each lamp 24 mustincorporate thereby decreasing the volume of the module that isimplanted in, or attached to, the lamp envelope while increasing itsefficiency and heat handling capabilities. Conventional power factorcorrection circuits require acceptance of rather large components(frequently bulky capacitors) for bulk energy storage and filteringthereby increasing the volume of the module at the lamp should thatmodule include such circuitry. Thus, inclusion of the power factorcorrection in the master unit 20 relieves the lamps of that volumetricburden associated with that function. Master ballast units 20 containinput filters, preferably along with suitable power factor correctioncircuits, to convert the 60 Hz power internally to a high voltage D.C.while presenting better than 0.99 power factor loading to the A.C.source.

The major sections of the master ballast 20 are shown in sequentialblock form in FIG. 3. The 110/220 VAC input 10 is initially passedthrough surge protection unit 26 where it is also filtered. The activepower factor of the filtered output from block 26 is corrected initiallyin block section 27 via conventional control circuitry. The A.C. is nextrectified in block 27 which can include other electronic functions, ifdesired, such as fault detection. Output power switching is accomplishedby a network of output diodes and filters 29 which finally produces theD.C. desired for output bus 22. Thus the power conditioningfunctionality and complexity of a traditional ballast is concentrated inone, much higher powered unit 20. Typically, master ballast 20 iscapable of driving a bank of thirty or more ballast lamps where thoselamps include their own oscillator circuit and gas discharge operatingcomponents, such as described later herein, for instance.

In operation, master ballast 20 (shown in general block form in FIG. 3)receives the input power from a conventional power main 10. The primaryinput power 10 is initially passed through circuitry 26 for surgeprotection and common mode and differential filtering. The A.C. is thenrectified and appropriate power factor correction reflected back intothe primary mains 10 via circuit 27 which likewise drives the controlelectronics. Output diodes and filters apply the resulting output fromcircuit block 29 into secondary lamp feed bus 22.

A block diagram of an embodiment of a ballast lamp 100 is shown in FIG.4. The key to utilizing existing fluorescent lamp design with its 20,000plus hours of life expectancy is to provide adequate heating power tothe cathodes 101 and 102. For ballast lamp 100, this is accomplished byrouting two thin wires 104 and 105 down the lamp wall to the end heater102. The potential difference between these wires is developed by thepower oscillator 108 in assembly 106 and its associated outputtransformer 109. After lamp ignition, as in conventional ballasts, thispotential is approximately 2.5 volts RMS. The power oscillator 108similarly heats the local heater or cathode 101. The high voltagestarting and running potential are established as in a conventionalballast across the secondary of the power oscillator output transformer109. The potential difference between local heater 101 and end heater102 is thus 110 VRMs during normal lamp operation. This potential is,however, in the form of a high frequency sine wave with a nearly perfectcrest factor (1.414).

As shown in FIG. 5, the power oscillator assembly can take the form of acylindrical unit 110, containing the hybrid electronics and miniaturizedmagnetics. Four leads 111, 112, 113 and 114, which are internal to theenvelope of tube 115, are connected to respective output pairs 116 and118 of module 110, and the entire power oscillator assembly ispreferably bonded to tube 115 somewhat like the manner a two-prongedendcap is attached to contemporary fluorescent lamps.

The lamp shown in FIG. 5 is intended for a system wherein the A.C. mainpower is converted to D.C. power at a remote unit (such as masterballast 20 of FIG. 2B) which is then connected to the lamp. Thus, thetwo different shaped electrodes 120 and 121 are respectively cylindricaland rectangular, and serve to key the lamp during installation so thatthe correct polarity of the high voltage D.C. is applied. A rectangularcross-section is acceptable for cylindrical terminal 120, althoughpreferably at 90° to ground terminal 121 to provide an alternatepolarity protection scheme. The internal electronic oscillator alsocontains reverse polarity protection to prevent tube damage forimproperly-wired ballast lamp sockets.

Note that keying of the connection electrodes is not necessary if themodule 110 employs a full wave rectifier, such as a diode bridge whichcan handle any polarity, and protects against polarity reversal. It isacceptable to employ pins similar to a contemporary fluorescent lamp forease of installation, but preferably with a different pin orientationsuch as wider or narrower spacings between the pins. This would preventinadvertent installation of the lamp in a conventional fixture.

The outside shell of the oscillator assembly 110 is constructed of athin sheet of ferrous metal. The internal electronics are mounted to ametal substrate which is attached to the outer shell. Thus, a heatconduction path is established to help minimize the internal electronictemperatures. The metal also serves as an electromagnetic shield tominimize radiation. The shell may further be attached to the metalstructure of lamp fixtures to further increase the heat sink capabilityof the ballast lamp.

FIG. 6 is a schematic diagram of the power oscillator which is aminiaturized electronic ballast configured to fit inside the fluorescenttube. Most (ninety-five percent or more) of the components are surfacemount devices. The exceptions are components, such as the transformer,including primary 130 and secondaries shown at 134 and 135, bulk storagecapacitors 131 and 132, inductive coupler 133, and several diodes.Circuit board pins 136 and 137 are connected to the two prongs at oneendcap of the fluorescent tube. A.C. power 10, typically 90 to 130 voltsRMS, 50 or 60 Hz, is applied to the tube.

The far end heater of the tube is connected via wires passing the lengthof the tube. While external placement of the end heater wires isacceptable, they are preferably inside the tube and coupled to circuitboard pins 143 and 144 of the output transformer secondary 135. The nearend heater of the tube is connected to pins 145 and 146. The tube socketcontaining pins 136 and 137 and the power oscillator circuit are oneintegrated part that is mated with the tube wires at the time of tubeassembly either permanently or detachably.

In operation, the FIG. 6 power oscillator functions as follows.Transient voltage suppressor (TVS) 140 prevents spikes and surges fromdamaging the electronics. Capacitor 141 and inductive coupler 133, alongwith capacitor 142, form a common mode EMI filter. Diode bridge 148 isan integrated circuit diode bridge for rectifying the input A.C. power.Resistor 151 and Zener diode 150 are a bootstrap circuit (typically 15volt) to supply initial power to integrated circuit chip 156. Resistors152 and Zener diode 153 likewise provide +5 volt bootstrap power forintegrated circuits 156, 157 and 158. Capacitors 154 and 155 are bulkstorage capacitors for these DC supplies.

Secondary winding 134, diodes 161 and 162, and resistor 163 feedauxiliary power to the +5 and +15 volt supplies after the poweroscillator has started. Integrated circuit 157 is a CMOS 555 timer chipwhich provides several hundred kilohertz clock signals to integratedcircuit chip 158. The network of resistors 164 and 165 and capacitor 166set the oscillator frequency while capacitors 167 and 168 are noisedecoupling capacitors. Clock signals from chip 157 are fed to chip 158which is an HCT74 flip-flop coupled to divide the oscillator clocksignals by two to provide a symmetrical square wave signal to integratedcircuit 156. While the circuit disclosed was constructed to produce anoutput signal at transformer 130 with a frequency of 220 kilohertz, itis believed advantageous to design the circuit to function in themegahertz range.

Integrated circuit 156 is preferably an IR2110S gate driver circuit.Power MOS FETS 171 and 172 are connected in a half-bridge configurationto drive the primary 130 of the output transformer. Capacitor 173 is thebootstrap capacitor for chip 156, while diode 162 is the charging diodefor capacitor 173. Capacitors 174 and 175 are decoupling capacitors forchip 156. Networks of resistor 176 and diode 177, as well as resistor178 and diode 179, prevent cross-conduction of 171 and 172, therebyminimizing power loss and EMI generation. It is possible to realizecross-conduction prevention by including some AND gates between theoutput of the divider circuit 158 and the driver chip 156. Such gateswould logically AND the short pulses from the oscillator circuit 157with the divider 158 output to prevent cross-conduction at the outputFET transistors 171 and 172 which drive the primary of outputtransformer 130.

Capacitor 180 is the resonant tank capacitor for the output transformerso that while square wave drives appear across primary 130, aquasi-sinusoidal drive is actually applied to the fluorescent tube.After tube ignition, windings 184 of secondary 135 applies approximately100 volts RMS across the tube, while windings 183 and 185 apply power(such as at 2.7 volts RMS) across the far-and-near end heaters,respectively.

An exemplary combination of electronic elements adapted for use inconjunction with the envelope of a gas discharge lamp is presented inFIG. 7. The planar circuit board 186 is shown with through-hole mountedcomponents 187-191 on the upper surface, and surface mounted components192-195 on the lower surface of board 186. Element 187 might represent adiode bridge assembly, while 188 and 189 are resistors and 190 and 191are bulk capacitors or inductor type components. The surface mountedelements 192-195 might include integrated circuit chips, surface mountedresistors and capacitors or the like.

Board 186 has a receptacle 198 mounted on one end as shown for receivingthe pins of array 199 extending from output transformer 200. A group offour leads 201 extend from transformer 200 to provide the connections tothe heater elements, such as 143-146 of FIG. 6, and the heaterconnections of FIG. 4 for instance. Another group of four leads 205couple the primary of the transformer and the secondary winding whichfunctions with the oscillator circuit, such as the FIG. 6 transformerprimary 130 and secondary winding 134.

Although not shown in FIG. 7, outer end 196 of board 186 preferablywould mount within an end cap having dual power connecting prongs forreceiving the A.C. or D.C. input power. Note that the opposite end (suchas end 107 of lamp 100 in FIG. 4) can have any of a variety of knownmounting structures as desired. It could include dummy pins similar tocontemporary fluorescent lamp bulbs if contemporary fluorescentreceptacles elements are employed. Otherwise, a blank endcap andreceptacle would suffice for retaining the bulb within a fixture.

FIG. 8 illustrates yet another embodiment of a gas discharge lamp 210having the elongated envelope 211 constructed preferably with a tubular,or semi-circular, cross-section but in a "U" shape. Base 215 is securedto envelope 211 as shown with pins 216 and 217 adapted to plug into anA.C. receptacle to provide the primary power source. The thus receivedA.C. power is connected to a module composed of a board 220 and outputtransformer 221. Board 220 has the oscillator circuit and othercomponents and circuitry including the power factor correction circuitmounted thereon for driving the output transformer 221.

The module, including board 220 and transformer 221, can be encapsulatedin a heat transferring material so as to completely fill the end of theenvelope 211 in which it is placed. Otherwise, the interior of envelope211 is filled with a gas discharge medium for producing visible lightupon excitation. Heater element 222 is connected directly to a pair ofoutput connections of transformer 221, while leads 223 pass fromtransformer 222 through the wall of envelope 211 into the base 215 andthence through the wall of envelope 211 on its opposite end so as toconnect with heater element 224. Note that it is possible to suppressundesired radio frequency radiation from the device by shielding, or byferrite beads on the output leads as is conventional.

While the exemplary preferred embodiments of the present invention aredescribed herein with particularity, those having normal skill in theart will recognize various changes, modifications, additions andapplications other than those specifically mentioned herein withoutdeparting from the spirit of this invention.

What is claimed is:
 1. A module for driving a gas discharge lamp havingheater elements contained within an envelope in response to electricalpower from a source comprising:means for receiving power from thesource, an oscillator coupled to said receiving means for transformingsaid received power to an output signal at a frequency and voltage forcausing the lamp to produce visible light through gas discharge withinthe lamp envelope, an a circuit board mounting said oscillator within avolume having a cross-section configured substantially the same as thecross-section of the lamp envelope, and means attaching said board forforming an end of the lamp envelope with said oscillator output signalconnected to the lamp heater elements.
 2. A module in accordance withclaim 1 wherein said circuit board is attached externally to an end ofthe lamp envelope, said module including a sleeve retaining said boardtherewithin.
 3. A module in accordance with claim 1 wherein the powersource produces standard A.C. power, said module further including meansmounted on said circuit board for converting said received power foractuating said oscillator.
 4. A module in accordance with claim 1wherein the power source produces D.C. power, said module furtherincluding means for actuating said oscillator from said received powerfrom the D.C. source.
 5. A module for driving a gas discharge lamphaving heater elements contained within an envelope in response toelectrical power from a source comprising:means for receiving power fromsaid source, an oscillator coupled to said receiving means fortransforming said power to an output signal at a frequency and voltagefor causing said lamp to produce visible light through gas dischargewithin aid lamp envelope, a circuit board mounting said oscillatorwithin a volume having a cross-section which is substantially the sameas a cross-section of said lamp envelope, and means for attaching saidcircuit board so that said oscillator output signal is connected to saidlamp heater elements.
 6. A module for driving a gas discharge lamphaving heater elements contained within an envelope in response toelectrical power from a source comprising:means for receiving power fromsaid source, an oscillator coupled to said receiving means fortransforming said received power to an output signal at a frequency andvoltage for causing said lamp to produce visible light through gasdischarge within said lamp envelope, a circuit board having saidoscillator mounted thereon, and means attaching said circuit board forforming an end of said lamp envelope with said oscillator output signalconnected to said lamp heater elements.